BAGHDAD
— The problem of low Sunni turnout in Sunday's elections has dominated discussion among senior Iraqi officials and US diplomats for months now. The fear is that it could deepen the insurgency and lead to a civil war between Sunni Arab insurgents and the Shiite Arab majority, who are likely to take power for the first time in Iraq's history.

One recent poll shows that up to 80 percent of Iraq's eligible Shiite and Kurdish voters will cast ballots. But Sunni turnout is pegged at 20 percent - or less.

Perceptions of the legitimacy of this democratic process, and thus the future stability of Iraq, may hinge on how many Sunnis vote, say analysts.

With the election just days away, a US-financed television ad blitz is now under way to persuade Sunnis they have more to lose than gain from standing outside the process. At least 10 ads a day will be carried until election day on Al Arabiya, one of the Arab world's most popular television stations, as well as on two other Arab satellite stations and local Iraqi TV.

As US and Iraqi officials scramble to coax Sunnis to the polls, they are also putting pressure on the likely election winners to create a special role for Sunnis in the writing of Iraq's new constitution, the major task ahead of the 275 legislators whom Iraqis will choose.

"Everyone understands that we need significant Sunni participation if Iraq's transition is going to work,'' says a US diplomat in Baghdad. "Preferably, that participation will be in the election, but at least in the drafting of the constitution."

Turnout is crucial because it will determine how many votes will be required to win a seat in the assembly. A Sunni turnout of anything less than 20 percent of the total vote (their estimated percentage of the Iraqi population) means Sunnis will be under-represented in the new parliament.

Wednesday's violence did little to raise hopes for a major Sunni turnout. A US convoy was attacked on the road to Baghdad's airport, two schools scheduled to be used as polling places were firebombed, and six other bombs were found and defused in the capital. Elsewhere, 31 marines were killed in a helicopter crash in western Iraq; in Ramadi, there were clashes between insurgents and Iraqi forces; and Al-Arabiya broadcast a videotape of three election workers kidnapped in the troubled northern city of Mosul. All of the incidents occurred in heavily Sunni areas.

Iraq's Shiite majority, who make up about 60 percent of the population, are eager to vote, as are the Kurdish minority in the north. Both groups suffered heavily under Saddam Hussein's Sunni-dominated regime, and a poll concluded on Jan. 7 by the US-funded International Republican Institute (IRI) found that nearly 80 percent in both communities say they are very likely to vote. Election officials say actual numbers will probably be below these figures.

"What people say they're going to do and what they actually do is not always the same,'' says a Western election adviser. "People are reluctant for or a variety of good reasons - if a bomb goes off and they feel they need to stay away for the safety of their family, that's very understandable."

"We'll vote and serve the people because that's what the hawza has told us to do,'' says Sheikh Ali al-Jumali, a Shiite preacher in Baghdad, referring to Shiite religious leadership. "We are going to do good by voting."

But in Sunni areas, only 20 percent of eligible voters said they are very likely to go to the polls on January 30, setting the stage for more sectarian and ethnic friction in a country that is already swamped by daily violence.

Calculating from the "very likely" voters from the IRI poll, Sunni Arabs are projected to make up about 6.5 percent of the voters. The closer the actual number gets to 20 percent of voters, the more the new government can claim legitimacy.

"There's going to be a very low turnout in four [predominantly Sunni] provinces which will give a distorted picture of what Iraqis want,'' says Adnan al-Pachachi, a Sunni Arab politician and former Iraqi representative to the UN who is leading a party list in the elections. "It isn't a good beginning for a democratic experiment."

Turnout also looks to be low among Iraqi expatriates. About 1.2 million of Iraq's 15.5 million eligible voters live abroad, and the International Organization for Migration, which is coordinating the expatriate vote, says only about 21 percent of the eligible overseas voters have registered.

US and Iraqi officials here hope the television ad campaign will change the current low Sunni turnout projections, and have enlisted one of Iraq's most beloved actors, Khalil al-Rafaee, to star in several of the ads after focus groups showed his credibility is particularly high among Sunni Arabs.

Mr. Rafaee is largely unknown in the West, thanks to a historical twist of fate. On July 14, 1958, he received a telex from British director David Lean asking him to play Sharif Ali al-Quraysh in the epic 1962 film "Lawrence of Arabia." But the next day, the British-installed Iraqi monarchy was overthrown in a bloody coup and the borders sealed. The role went to Egypt's Omar Sharif.

One TV spot opens with Rafaee walking with a friend by the river. His friend turns to him. "We need more time, Khalil, this is all happening too fast." Khalil nods understandingly, "Yes, we used to have more time,'' he says, "but did we have any choices then?"

The friendly back and forth carries on for a few more moments and then Khalil asks his skeptical friend, "Soon it will be election day. What will you do then?"

"I'll just come back and watch the river,'' he friend replies. "And you?" Khalil pauses. "God willing, I'll wake up and decide whether I'm ready to make a difference."

In another, Khalil sits with his grandson, who recounts explosions and the recent killings of election workers. Khalil tells him, "Yes, it's terrible. But we have to show people that they can't take this away from us." In yet another spot, voters are told that participating if they want the US occupation to end, they should get out and vote.

It's a soft-shoe approach US officials hope will make a difference, laying out options for viewers rather than preaching to them about the merits of democracy.But it's vying with an increasingly menacing insurgency, members of which have distributed leaflets in a number of towns in recent days warning that if people go to the polls, they'll be found and killed at their homes.

Farid Ayar, a spokesman for Iraq's Independent Electoral Commission, says provisional election results may be available on Feb. 6 and that final results are expected to be available on Feb. 9.

Security rules at voting stations are inhibiting major organizations from doing exit polls. The rules require pollsters to stand about 700 yards away from polling places - outside the security cordons - making it too hazardous to carry out the polls.